Background: High frequency component in spectral analysis of intracardiac electrogram might be associated with structural inhomogeneity of underlying cardiac tissue, which could be a substrate of arrhythmia. Methods & Results: Seven consecutive patients (49짹16 years, M:F = 2:5) with successfully ablated right ventricular outflow tract (RVOT) tachycardia were enrolled. Four endocardial bipolar electrograms, which were obtained at the first successful ablation site (S site) and the last three failed sites (F sites) just before the successful ablation, were analyzed in each patient. Spectral analysis of each electrogram was performed using fast Fourier transformation. The area under the spectrum curve in the range of frequencies lower than 100 Hz was defined as a low-frequency component (LF), and that of 100 Hz or higher was defined as a high-frequency component (HF). The LF/HF ratio was calculated for each electrogram. Total seven S-site and 21 F-site electrograms were evaluated. S sites showed lower LF/HF ratio than F sites (2.99짹0.91 vs. 4.77짹2.71, p < 0.05, *Figure). Conclusion: Spectral analysis of local electrogram could be helpful for target selection in catheter ablation of RVOT ventricular tachycardia.